The present invention relates to treating of food products and more particularly to treating food materials under heat and pressure.
In the past, food materials have been processed under heat and pressure using various types of apparatus and methods. Starch materials, for example, have been gelatinized by forming a a dough and then treating the dough in a puffing gun as shown in U.S. Pat. No. 3,231,387. Such puffing guns have not been suitable for treating material in the form of fine particulate material such as flour. Recently method and apparatus was discovered which is suitable for treating such fine particulate material. Such method and apparatus is disclosed and claimed in U.S. Pat. No. 3,730,729. The present invention is an improvement on the method and apparatus of U.S. Pat. No. 3,730,729.
The materials that may be processed according to the present invention are many and varied. The materials include any material that is reactive in the presence of the heat and pressure of the present invention. The reaction may be either a chemical or a physical reaction. The processing of the present invention may include one or more of the following: gelatinization, texturization, puffing, homogenizing and agglomerating.
One illustrative class of materials that may be processed according to the present invention includes the cereal flours and mixtures of cereal flours with other materials. The cereal flours typically include wheat flour, corn flour, rice flour, tapioca and the like. Another similar starchy fine particulate material is potato flour. One reaction that takes place when such starchy materials are subjected to the heat and pressure of the present invention is gelatinization.
Another class of reactive materials that may be treated according to the present invention is protein materials. In recent years substantial effort has been directed toward treating vegetable protein materials so as to provide such materials with texture and other characteristics commonly found in animal meat products. The vegetable protein materials are primarily soybean meal and flour, however, various other oil seed meals and flours also are used, such as peanut, cottonseed and sesame seed meals and flours. It is generally preferred to use protein concentrates of such oil seed meals typically including at least about 50% protein by weight. Untexturized protein material contains protein in discrete particles. Texturization takes place when the protein acquires a substantially continuous phase. The texturized material, when moist, is somewhat tough or chewy much like meat. The term "texturizing" as used herein will refer to the process of changing the discrete particles of protein into continuous phase protein.
It was recently discovered that finely-divided particulate protein material may be texturized by passing the material in a stream of gaseous fluid through an elongated cylinder or pipe and applying elevated pressure and temperature. This recently discovered method provides highly satisfactory texturized protein. Such method is disclosed and claimed in U.S. Pat. No. 3,754,926. The previous method necessitated use of a pressure tank or surge tank to maintain an elevated processing pressure in the cylinder or pipe. This was because the flow of gaseous fluid into the pipe or cylinder was discontinuous or pulsating. The present invention provides improved and simplified apparatus. For example, the need for a pressure tank has been eliminated in the present invention by provision of a continuous flow of gaseous fluid into the pipe or cylinder.
The protein material to be processed according to the present invention may be of the type used in previous texturizing processes and typically includes the various defatted oil seed meals and flours such as soybean, peanut, cottonseed and sesame. Various other untextured protein materials such as wheat gluten, yeast, sodium, caseinate and the like may be texturized according to the present invention. The protein material used in the present invention is preferably a flour-like material, particularly soybean flour which may have a protein content of 30% or more by weight.
A further class of reactive materials that may be treated according to the present invention includes those materials that may be homogenized. This class includes the oil containing materials such as finely ground dutched cocoa. The fat is normally present in cocoa powder as fat globules. In the process of the present invention the fat globules are broken up and uniformly distributed throughout the powdered particle thereby providing a dark cocoa product. The processed cocoa material disperses more readily in water than does the untreated cocoa powder. The cocoa is also agglomerated and puffed. A sugar and flour mixture may also be homogenized. The sugar is believed to melt and become uniformly spread on the surface of the flour.